Comparison of two jam making methods to preserve the quality of colored carrots

In this study, carrot jams were developed using either precooked vegetable (common method) or short cooking times (mild method). Jams were prepared using four carrot types: a commercial one and three local landraces (orange, purple and yellow). The parameters assessed were total phenols, antioxidant activity, beta-carotene, potassium content, color and sensory evaluation. Mild method caused lower color differences than common method, when comparing the jams to raw carrots. Antioxidant activity, total phenols and potassium content loss were also lower in mild method. Both methods improved beta-carotene retention in jams. Following sensory analysis, products obtained by mild method showed the best scores for taste and overall acceptability, with the highest scores being registered for purple jam. In particular, high correlations between antioxidant activity, total phenols and purple products (both raw products and jams) were emphasized by principal component analysis. In conclusion, the mild method described in this paper helps to preserve the overall quality of perishable vegetables, such as local carrots. (C) 2013 Elsevier Ltd. All rights reserved.